AIUI, the thing that makes a vaccine's effectiveness very short term, like flu vaccines, is the natural evolution of the virus, not its effect on the immune sys

AIUI, the thing that makes a vaccine's effectiveness very short term, like flu vaccines, is the natural evolution of the virus, not its effect on the immune system. It's not that people who got a 2015 flu aren't still immune to the 2015 flu, it's that wild flu virii look different in specific ways that cause them to slip by. As such, I think these drug companies don't really have much to release for each vaccine. (That isn't to say the immune system can't forget immunity - TDAP boosters are for evolution, but for refreshing the immune system - but that super short term immunity like flu, AIUI, is about the virus not the vaccine.)